The present invention relates generally to a printer, more particularly a serial printer that prints images on a medium with a print head mounted on a reciprocating carriage that is driven by a motor. The present invention provides a printer with a novel and improved motor mounting structure for damping noise associated with vibrations of the printer motor.
In a printer, a motor that drives a carriage to reciprocate, enabling a print head mounted on the carriage to print data, makes noise when vibrations from the frequent and repeated forward and reverse operations of the motor are transmitted to the printer frame. To lessen the noise, damping structures have been devised, wherein shock absorbers are placed between the motor and the printer frame on which the motor is mounted.
One example of such damping structure is described in Unexamined Japanese Patent Publication No. Sho. 59-136280, and shown in FIG. 5. In reference to FIG. 5, a motor, generally indicated as 1, is fixed to a frame 2 through shock absorbers 3 by screws 4 and nuts 5. Each shock absorber 3 has an annular groove 3a on the outer circumference thereof, and annular groove 3a must be force-fitted into a hole 2a formed on frame 2. Since shock absorber 3 also includes flanged portion 3b, which has larger diameter than that of hole 2a, and since flanged portion 3b must be forced through hole 2a in order to force-fit annular groove 3a into hole 2a, this force-fitting process becomes a cumbersome operation. Moreover, such force-fitting is likely to cause breakage of shock absorber 3 or deformation of frame 2.
These problems can be overcome by changing the shape of hole 2a, as shown in FIG. 6. In reference to FIG. 6, each hole 2a of frame 2 is formed into a snowman-like shape that, in addition to having a small diameter hole, has a large diameter hole 2a'. Large diameter hole 2a' is of sufficient size to allow easy insertion of flanged portion 3b into it. Once flanged portion 3b is inserted into large diameter hole 2a', annular groove 3a is force-fitted into hole 2a by moving shock absorber 3 in the direction indicated by an arrow b.
The presence of large diameter hole 2a' makes fitting of annular groove 3a into hole 2a less cumbersome, and decreases the risk of damaging shock absorber 3 or frame 2 in the fitting process. However, this structure poses a different problem in that by making large diameter holes 2a', which would otherwise be unnecessary, the strength of frame 2 is reduced.
Accordingly, the present invention provides a printer having noise damping shock absorbers, which can be easily attached to the printer frame, without unnecessarily reducing the strength of the frame.